Chapter 4: Tissue: The Living Fabric (B)

Connective, Muscular, Nervous Tissue

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Connective Tissue

found everywhere in the body, it is the most abundant and widely distributed tissue type. 3 main elements: ground substance, fibers, and cells. (ground fibers and cells make up the extracellular matrix

white fibers; are by far the strongest and most abundant. Provides high tensile strength

Elastic Fibers

long, thin fibers that form branching networks in the extracellular matrix. Contain rubber like protien, elastin, that allows them to stretch and recoil like rubberbands.

ex: skin, lungs, blood vessels

Reticular Fibers

short, fine, collagenous fibers with a slightly different chemistry and form. They are continous with collagen fibers and are higly branched forming delicate vessles. Abundant where connective tissue abuts other tissue types. Has ability to catch water.

ex: basement membrane of epithelial tissues, and ground capillaries, high degree in plasma

Function: bone supports and protects (by enclosing); provides levers for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation (hematopoiesis)

Location: (bones)

Others: blood

Description: red and white blood cells in a fluid matrix (plasma)

Function: Transport of respiratory gases, nutrients, wastes, and other substances

Location: contained within blood vessels

Nervous Tissue

the main component of the nervous system - the brain, spinal cord, and nerves - which regulates and controls body functions

Description: Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonirritable supporting cells (not illustrated)

Function: transmit electrical signals from sensory receptors and to effectors (muscled and glands) which control their activity

Location: brain, spinal cord, and nerves

Muscle Tissue

highly cellular, well vascularized tissues that are responsible for most types of body movement. Muscle cells contain mayofilaments, elaborate versions of actin and myosin filaments that bring about movement or contraction in all cell types.

first event of embryonic develpoment is the formation of three primary germ layers. (Superficial to deep) ectoderm, mesoderm, and endoderm. These germ layers specialize to form the four primary tissues (epithelium, connective, nervous, and muscle)

Germ Layers

Nerve tissue arises from ectoderm, Muscle and connective tissues arise from mesoderm, Epithelial tissues arise from all three germ layers